#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
int main(void)
{
    int n;
    double score, sum = 0, average;
    printf("the number of students:");
    scanf("%d", &n);
    printf("the scores:");
    if (n <= 0) {
        printf("average=0.00\n");
        return 0;
    }
    for (int i = 0; i < n; i++) {
        scanf("%lf", &score);
        sum += score;
    }
    average = sum / n;
    printf("average=%.2f\n", average);
    return 0;
}
